In conventional manner, in a bypass turbojet having an after-burner chamber, a burner ring is mounted on the radially-outer ends of flame-holder arms which are themselves secured to the outer casing of the after-burner chamber, and a circular fuel injection duct extends inside the burner ring. The circular duct is connected at a plurality of points to fuel feeds on the outer casing of the after-burner chamber via feed ducts which extend radially between the outer casing and the burner ring. These feed ducts pass through the secondary stream of the turbojet that flows between the outer casing and an internal cylindrical wall defining the after-burner chamber where the burner ring is located and having flowing therein the primary flow formed by the exhaust gas coming from the combustion chamber of the turbojet. These ducts are generally put into place and secured from inside the after-burner chamber.
It would be advantageous to house the fuel feed ducts of the burner ring inside outer end portions of the flame-holder arms in order to protect these ducts from the primary flow which is at a high temperature (that can reach about 2000°K in after-burner mode, for example) and in order to avoid disturbing the primary flow, but known means for fastening such ducts to the outer casing have parts that pass through the wall that are of relatively large diameter, so they are unsuitable for passing via the insides of the flame-holder arms.
In addition, the space available between the outer casing of the after-burner chamber and the internal cylindrical wall downstream from the burner ring is too small for it to be possible from the inside to fasten these feedthrough parts to the outer casing by using tools engaged inside the outer casing downstream from the burner ring.